EP4137708A1 - Expansion anchor - Google Patents
Expansion anchor Download PDFInfo
- Publication number
- EP4137708A1 EP4137708A1 EP22200871.6A EP22200871A EP4137708A1 EP 4137708 A1 EP4137708 A1 EP 4137708A1 EP 22200871 A EP22200871 A EP 22200871A EP 4137708 A1 EP4137708 A1 EP 4137708A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- hollow shaft
- bolt
- radially expansive
- radially
- expansive portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000009434 installation Methods 0.000 claims abstract description 50
- 239000002184 metal Substances 0.000 claims description 15
- 230000004323 axial length Effects 0.000 claims description 6
- 239000012141 concentrate Substances 0.000 abstract 1
- 238000003825 pressing Methods 0.000 description 11
- 239000000725 suspension Substances 0.000 description 10
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000011161 development Methods 0.000 description 5
- 230000018109 developmental process Effects 0.000 description 5
- 238000012423 maintenance Methods 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000003801 milling Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
- F16B13/12—Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like
- F16B13/124—Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like fastened by inserting a threaded element, e.g. screw or bolt
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
- F16B13/04—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front
- F16B13/08—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front with separate or non-separate gripping parts moved into their final position in relation to the body of the device without further manual operation
- F16B13/0891—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front with separate or non-separate gripping parts moved into their final position in relation to the body of the device without further manual operation with a locking element, e.g. wedge, key or ball moving along an inclined surface of the dowel body
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
- F16B13/04—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front
- F16B13/08—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front with separate or non-separate gripping parts moved into their final position in relation to the body of the device without further manual operation
- F16B13/0833—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front with separate or non-separate gripping parts moved into their final position in relation to the body of the device without further manual operation with segments or fingers expanding or tilting into an undercut hole
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
- F16B35/005—Set screws; Locking means therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B37/00—Nuts or like thread-engaging members
- F16B37/12—Nuts or like thread-engaging members with thread-engaging surfaces formed by inserted coil-springs, discs, or the like; Independent pieces of wound wire used as nuts; Threaded inserts for holes
- F16B37/122—Threaded inserts, e.g. "rampa bolts"
Definitions
- the present invention relates to an expansion anchor of the type in which a portion of a hollow shaft is bulged by screwing of a bolt.
- Expansion anchors are used to attach various members such as fittings to stony structures made of concrete or the like, as in the case where various members are suspended from the inner surface of a tunnel, for example.
- expansion anchors There are various types of expansion anchors.
- the tip end of a hollow shaft (anchor body) is divided by a plurality of circumferentially separated longitudinal slits to provide an radially expansive portion (expansion portion), and the radially expansive portion is bulged utilizing a wedging action caused by screwing of a bolt.
- expansion anchor of the type that utilizes, instead of a bolt, a pin with a tapering tip portion having a progressively decreasing diameter toward the tip end.
- the pin is impacted with a hammer for insertion into the hollow shaft.
- Patent Document 1 There is also a proposal in which an anchor body is expanded indirectly instead of being directly expanded with a bolt.
- a ball made of metal is inserted into a radially expansive portion for bulging the radially expansive portion due to an expanding action caused by the ball.
- Patent Document 2 also discloses a similar configuration.
- Patent Documents 3 and 4 disclose use of a fusiform member as a radially expanding member instead of the ball.
- the expansion anchors disclosed in the patent documents and the hit-type expansion anchors provide a withdrawal resistance by expanding the radially expansive portion located at the tip end of the hollow shaft into a flaring shape and pressing the radially expansive portion against a pre-formed hole.
- the withdrawal resistance of the conventional expansion anchors is fixed theoretically.
- a troublesome problem regarding an expansion anchor is a phenomenon called cone-type failure wherein a portion of concrete centered around the expansion anchor at the installation region comes off in the form of a cone. Such a cone-type failure occurs due to the expansion of the radially expansive portion of the anchor. Therefore, in order to prevent the cone-type failure, an expansion anchor is designed in a manner such that the radially expansive portion thereof do not expand excessively, which is one of the detrimental factors in enhancing the withdrawal resistance.
- a more troublesome problem is that, when an anchor is engaged into the ceiling of a concrete tunnel for example, the weight of a workpiece acts as a downward load on the expansion anchor, and this downward load may cause cone-type failure. In other words, even if there appears no problem at the time of installation, a cone-type failure occurs as a delayed failure upon lapse of time.
- the present invention which has been conceived in light of the aforementioned circumstances, provides an expansion anchor that keeps a high withdrawal resistance while also providing a high functionality for preventing a cone-type failure.
- the present invention includes various structural features. Typical aspects thereof are identified as first to fifth inventions.
- the first invention is a generic invention which provides an expansion anchor includes a hollow shaft to be inserted, from a tip end thereof, into a pre-formed hole formed in an installation region, and a bolt to be screwed into the hollow shaft from outside the installation region, wherein the hollow shaft is formed with a radially expansive portion, that is weakened to be bulgeable, at a portion of the hollow shaft within the pre-formed hole and short of the tip end of the hollow shaft, and the hollow shaft is internally provided with a radially expanding action member that pushes the radially expansive portion radially outward in response to pushing action caused by screwing of the bolt into the hollow shaft.
- the hollow shaft does not need to be open at both ends if at least its base end (to be located outside of the installation region) is open. Therefore, the tip end to be inserted into the pre-formed hole may have a solid structure. Further, according to the present invention, a plurality of radially expansive portions can be provided. These are the major features of the present invention.
- the expansion anchor may usually have a perfect circular shape, but its shape is not necessarily limited to a perfect circle in the present invention.
- the present invention may comprise a structure in which the entire hollow shaft or only the radially expansive portion is formed in a non-perfect circle such as an ellipse or a polygon.
- a non-perfect circular shape also include a shape that basically follows a perfect circle but has two flat faces which are parallel to each other.
- the pre-formed hole is generally formed in a perfect circular shape at the installation region using a rotating drill. However, when the hollow shaft has a non-perfect circular shape, the pre-formed hole may be processed into a non-perfect circle corresponding to the shape of the hollow shaft.
- the second invention is a development of the first invention in which the radially expansive portion of the hollow shaft is formed with a plurality of axially elongated slits that are circumferentially spaced from each other.
- a portion of the hollow shaft in which the slits are formed serves as a radially expansive portion.
- the number of the slits may be selected depending on the outer diameter or thickness of the hollow shaft. In general, three to six slits may be usually formed.
- the slits in a group may be arranged at circumferentially regular or irregular intervals.
- the third invention is a development of the first invention or second invention in which the radially expanding action member includes a multiplicity of metal balls, and the radially expansive portion is allowed to bulgingly deform due to the balls moving radially outward in group in response to a push from the bolt.
- the balls in the group may be entirely equal in diameter, or they may include a plurality of diametrically different balls.
- the fourth invention is a development of the third invention.
- the radially expansive portion has an axial length that is at least twice an outer diameter of the hollow shaft.
- the fourth invention may also be regarded as a development of the first invention or second invention.
- One major feature of the present invention is that the length of the radially expansive portion can be set to be extended.
- a member such as a fitting may be attached to the expansion anchor.
- the fifth invention is an implementation in this regard. More specifically, the fifth invention is based on the third invention, wherein wherein the hollow shaft is configured such that the other end is exposed outside the installation region, at least a portion of the hollow shaft that is exposed outside of the installation region is formed with fixing threads, and the fixing male screw is engageable with a nut for mounting another member.
- the fifth invention may also be regarded as a development of the first, second invention, or fourth invention.
- the radially expansive portion is located at a position short of the tip end of the hollow shaft. Therefore, the radially expansive portion does not expand into a flaring form but bulges expansively in a direction orthogonal to the axis. This bulging portion comes into biting engagement with the pre-formed hole at the installation region (made of concrete), consequently providing a resistance against withdrawal.
- One feature of the present invention resides in that the length of the radially expansive portion can be increased.
- the radially expansive portion having an increased length can come into deep biting engagement with the installation region, thereby contributing greatly to an increase in withdrawal resistance (namely, fastening strength).
- the expansion anchor is particularly useful as a fastening tool to suspend a member from a concrete ceiling of a tunnel or building. Furthermore, according to the present invention, when the hooking force of the radially expansive portion reduces due to a timewise damage of the installation region for example, the withdrawal resistance may be restored by screwing the bolt to expand the radially expansive portion. Therefore, it is easy to adjust the torque to keep the withdrawal resistance at an appropriate value. In the case where the bolt has slided down, it is preferable to expand the radially expansive portion again after pushing the bolt back to the original depth.
- the radially expanding action member can be easily retreated by screwing back the bolt, it is easy to pull out the expansion anchor, which has been once attached, against the elastic force of the radially expansive portion. Accordingly, it is also easy to remove an unnecessary anchor and replace it with a new one.
- the slits formed according to the second invention as a means for forming the radially expansive portion is preferable because this enables the radially expansive portion to bulge in a reliable manner. Moreover, when the radially expansive portion is divided by the slits into a plurality of circumferentially separated sections, a specific one or ones of the sections are more likely to bulge for more readily coming into biting engagement with the installation region to provide better hooking to the installation region. Accordingly, it is possible to provide a high fastening strength can be reliably obtained while preventing cone-type failure.
- Metal balls are widely used in various fields such as bearings, and various types of metal balls are commercially available. Therefore, when the metal balls are used as the radially expanding action member as set forth in claim 3, it is possible to suppress the manufacturing cost due to ready availability of metal balls requiring no dedicated manufacturing apparatus.
- the metal balls when used as the radially expanding action member, the metal balls come into point contact with the radially expansive portion from the inside, so that the entire circumference of the radially expansive portion is not pressed uniformly. Instead, only specific circumferential positions of the radially expansive portion are pressed outward by the metal balls. As a result, the area of engagement of the radially expansive portion with the installation region is reduced, so that the radially expansive portion can easily come into biting engage with the installation region. In other words, the radially expansive portion can easily come into deep engagement with the installation region in the manner of biting into the installation region. In this way, it possible to provide a high hooking force while suppressing the compressive force against the installation region.
- the metal balls as the radially expanding action member is advantageous in providing a high fastening strength without causing cone-type failure.
- the length (axial length) of the radially expansive portion may be selected depending on the required withdrawal resistance.
- the radially expansive portion has an axial length that is at least twice an outer diameter of the hollow shaft as in the fourth invention, the radially expansive portion can be bulged reliably, so that a high withdrawal resistance (fastening strength) can be secured more reliably.
- a checking operation may be performed by rotating the bolt using a torque wrench. However, if a suspended member has to be removed every time the bolt is rotated using a torque wrench, the checking operation becomes troublesome.
- the head of the bolt pressing the radially expanding action member can be kept exposed outside of the installation region, so that the bolt can be rotated using a torque wrench while a member such as a ceiling panel or a ceiling frame is kept suspended by the expansion anchor. Accordingly, a maintenance operation can be performed very easily for checking whether or not the withdrawal resistance of the expansion anchor is kept at a predetermined value and restoring the withdrawal resistance which has dropped.
- An expansion anchor includes a hollow shaft 3 to be inserted into a pre-formed hole 2 in an installation region 1 made of concrete.
- an end that will enter the pre-formed hole 2 is defined as a tip end 3a, and an opposite end is defined as a base end 3b.
- the base end 3b of the hollow shaft 3 is provided with a flange (or head) 4 having a hexagonal shape or a circular shape.
- the hollow shaft 3 is formed with a hole 5 over the entire length thereof, and the hole 5 has a small-diameter portion 5a within a certain range from the tip end 3a.
- the tip end 3a may have a solid structure in which the small-diameter portion 5a of the hole 5 is eliminated.
- the hole 5 may have a constant diameter over the entire length thereof, and the tip end 3a is closed with a plug.
- the hollow shaft 3 may also be formed by stretching a hollow coil pipe with a small-diameter hole. In this case, the inner diameter of the material coil pipe remains as the diameter of the small-diameter portion 5a, whereas the other portion of the hollow shaft is diametrically enlarged by drilling or the like.
- the material of the hollow shaft 3 may be selected as needed. When high durability and rust-resistance are required as in the case of anchors for tunnels, it is preferable to use a hollow shaft made of stainless steel. Steel that has undergone surface treatment such as plating is also preferable
- the hollow shaft 3 short of the tip end 3a there are formed four axially elongated slits 6 at regular circumferential intervals.
- the portion of the hollow shaft in which the slits 6 are formed serves as an radially expansive portion 7 that is bulgeable in a direction orthogonal to the axis. Therefore, the slits 6 do not extend into the tip end 3a of the hollow shaft 3. Further, the slits 6 communicate with the inside and outside of the hollow shaft 3.
- the slits 6 may be machined using a milling cutter, for example.
- the number of the slits 6 can be selected as desired. In the example shown in FIG. 1 (C'), six slits 6 are formed.
- the axial length of the radially expansive portion 7 is set to be about twice the outer diameter of the hollow shaft 3. When the radially expansive portion 7 has a small thickness, the radially expansive portion 7 can be easily deformed even if its length is shorter than twice the outer diameter of the hollow shaft 3.
- the hole 5 of the hollow shaft 3 is formed with a female screw 8 in a portion (toward the base end 3b) short of the radially expansive portion 7, and a hexagonal-socket bolt 9 is screwed into the female screw 8 from the outside (the female screw 8 may extend into the radially expansive portion 7).
- a multiplicity of metal balls (steel balls) 10 as an example of radially expanding action member, are accommodated between the bolt 9 and the tip end 3a.
- the outer diameters of the balls 10 are set to be slightly smaller than the inner diameter of the hole 5, and in the illustrated example, the balls 10 have an equal outer diameter. It will be appreciated that the outer diameter of the balls 10 may be set to be substantially equal to the inner diameter of the hole 5.
- the outer diameter of the hollow shaft 3 and the inner diameter of the hole 5 may be set as desired. In other words, the thickness of the hollow shaft 3 may be set as desired.
- a method of using the expansion anchor is similar to a conventional method. As shown in FIG. 1(E) , the hollow shaft 3 is fitted into the pre-formed hole 2 in the installation region 1, and then the bolt 9 is screwed thereinto using a hexagonal bit 11. This causes the group of balls 9 to be moved in a chain reaction manner. The adjacent balls 10 are in contact with each other, and therefore, the balls 10 also tend to move radially of the hollow shaft 3. As a result, the radially expansive portion 7 deforms expansively over a long range and engages with the pre-formed hole 2 in the installation region 1.
- the radially expansive portion 7 is shown to expand into a plateau shape by solid lines in FIGS. 1(E) and 1(F) .
- the radially expansive portion 7 is more likely to bulge in a mountain-like shape (or a bow shape) as indicated by a chain line in FIG. 1(E) because the balls 10 pressing against one another act such that the balls 10 located at weaker portions are pressed more strongly.
- the balls 10 come into point contact with the radially expansive portion 7
- the ball 10 that comes into contact with the weakest portion of the radially expansive portion 7 is most strongly pressed by the other balls 10, so that the radially expansive portion 7 is deformed in a mountain-like shape.
- the radially expansive portion 7 When the length of the radially expansive portion 7 is reduced, the radially expansive portion 7 inevitably bulges in a mountain-like shape or a bow shape.
- the radially expansive portion 7 is divided into a plurality of sections by the slits 6. It is more likely that the weakest one of these sections is concentratively bulged rather than all sections bulging uniformly. Therefore, in general, bulging may occur only at one circumferential position of the radially expansive portion 7.
- a radially expansive portion is denoted by a reference numeral 7a.
- the leading end of the radially expansive portion 7' moves as indicated by an arrow 7b, and a pressing force (compressive load) acts on the installation region 1 made of concrete as indicated by the arrow 7b.
- a boundary may be generated in the installation region 1 made of concrete between a portion pressed strongly by the radially expansive portion 7a and a portion not so pressed.
- the radially expansive portion 7a applies a pressing force in the direction 7b which is inclined relative to the anchor axis, and it is also speculated that the boundary is likely to form a conical surface, which may promote cone-type failure.
- the radially expansive portion 7 is deformed into a mountain-like shape or the like. It is thus speculated that the radially expansive portion 7 engages with the installation region 1 while biting into the structural material instead of strongly pressing against the installation region 1.
- the expansion anchor according to the embodiment of the present invention is hooked to the pre-formed hole due to biting rather than staying in the pre-formed hole due to friction. This makes it possible to achieve a high withdrawal resistance while preventing cone-type failure.
- the radially expansive portion 7 bulges in a direction orthogonal to the axis of the hollow shaft 3, so that a boundary may not be formed in the installation region 1 between a portion subjected to a strong pressing force and a portion not subjected to a strong pressing force.
- the pressing force (compressive stress) acting on the installation region 1 changes gradually in the axial direction, thereby contributing greatly to the prevention of cone-type failure.
- the hexagonal bit 11 is attached to a torque wrench.
- the pushing force of the radially expansive portion 7 against the pre-formed hole 2 is proportional to the screwing torque of the bolt 9. Therefore, when a predetermined screwing torque is reached by screwing the bolt 9 with a torque wrench, rotation of the bolt is stopped.
- the bolt 9 has deeply entered into the female screw hole 8 when the radially expansive portion 7 is bulged. Therefore, a member 13 can be fixed to the base end surface of the hollow shaft 3 by screwing a fastening bolt 12 into the female screw hole 8. Accordingly, a state has to be achieved in which the bolt 9 enters entirely into the female screw hole 8 to allow another bolt to be further screwed into the female screw hole 8 from the outside.
- the use mode of the expansion anchor may be set as desired depending on the conditions of the installation region.
- a suspension bolt is screwed into the hollow shaft 3 from below, and various members such as a ceiling panel is suspended by the suspension bolt (this example will be described later).
- the length of the radially expansive portion 7 is set as desired depending on the length of the hollow shaft 3, required withdrawal resistance, or the like.
- the base end 3a of the hollow shaft 3 is provided with no flange, but the second embodiment has otherwise the same structure as the first embodiment.
- the radially expansive portion 7 is shown to bulge in a trapezoidal shape. In reality, however, the radially expansive portion 7 is more likely to bulge in a mountain-like shape as indicated by the chain line in FIG. 1(E) .
- the third embodiment shown in FIG. 2 (B) and the fourth embodiment shown in FIG. 2(C) share a common structure in which the outer circumference of the hollow shaft 3 is formed with an engaging male screw 15 for engagement with the pre-formed hole.
- a flange 4 is formed at the base end 3b of the hollow shaft 3, whereas a straight structure of the hollow shaft without a flange 4 is obtained in the example shown in FIG. 2(C) .
- the engaging male screw 15 may have a pitch that is plural times larger than the thread width for facilitating the inserting engagement into the pre-formed hole 2 in the installation region 1.
- a plurality of threads having different heights may also be formed.
- the engaging male screw 15 when the flange 4 as shown in FIG. 2(B) is formed in a polygonal shape such as a hexagonal shape that can be rotated using a spanner (wrench), the hollow shaft 3 can be easily screwed into the pre-formed hole 2.
- the engaging male screw 15 is formed only up to a position short of the radially expansive portion 7.
- the engaging male screw 15 may be formed to extend also over the entirety of the radially expansive portion 7.
- the engaging male screw 15 formed to extend over the radially expansive portion 7 is expected to remarkably improve the withdrawal resistance because the engaging male screw 15 comes into strong biting engagement with the pre-formed hole 2 due to bulging of the radially expansive portion 7.
- a multiplicity of annular projections 16 are formed on the radially expansive portion 7.
- Each annular projection 16 has a cross-sectional shape of a right-angled triangle with its inclined surface oriented toward the tip end 3a, consequently providing a high withdrawal resistance.
- the annular projections 16A may be replaced with a spiral projection.
- the outer circumference of the radially expansive portion 7 may be knurled.
- a fixing male screw 16 for screwing engagement with a nut 17 is formed within a certain range on the base end side of the hollow shaft 3. Therefore, the fixing male screw 18 serves as a metric screw thread.
- a member 13 is formed with an attachment hole 19 in which the fixing male screw portion 16 is fitted, and the member 13 is pressed against and fixed to the surface of the installation region 1 using the nut 17. It is unnecessary to insert the bolt 9 entirely into the hollow shaft 3, so that a bolt with a head can be used as the bolt 9. Moreover, the radially expansive portion 7 may be made to bulge in response to operating the bolt 9 while the member 13 is fixed.
- the seventh embodiment shown in FIG.3 (B) is a modified example of the sixth embodiment.
- a flange 4 is provided on the hollow shaft 3
- a fixing male screw 16 is formed outwardly from the flange 4
- an engaging male screw 15 is formed on a side opposite to the fixing male screw 16.
- the flange 4 may preferably have a polygonal shape such as a hexagonal shape.
- an engaging male screw 15 is formed on the outer circumference of the hollow shaft 3, and an engaging hole 20 for fitting engagement with a polygonal bit 11 having a hexagonal shape or the like is formed at the base end of the hollow shaft 3. Therefore, a flange 4 may be unnecessary.
- the bolt 9 for bulging the radially expansive portion 7a has a hexagonal socket, and the bolt 9 is set to be exposed to the outside of the hollow shaft 3 even in the state where the radially expansive portion 7 is bulged.
- the member 13 is fitted over the bolt 9 and fixed thereto using a nut 17. Therefore, in this embodiment, the bolt 9 for bulging the radially expansive portion 7 is used to attach (fix) the member 13. Further, a rotational operation (torque adjustment) of the bolt 9 can be easily performed by loosening the nut 17.
- the nut 17 also serves to prevent the bolt 9 from loosening.
- a hole 5 is formed in the hollow shaft 3 over the entire length thereof, and a female screw 8 is formed in the hole 5 over the entire length thereof, and a stopper bolt 21 is screwed into the hollow shaft from the tip end thereof.
- use may be made of a pipe for forming the hollow shaft 3, thus contributing to a cost reduction.
- Female screws 8 may be formed only on two sides flanking the radially expansive portion 7.
- a milling cutter 22 that is machining the slits 6. Although the milling cutter 22 is shown to be moved in the figure, the hollow shaft 3 may be moved instead.
- a fixing male screw 16 such as shown in FIG. 3 (A) may be formed at the base end 3b of the hollow shaft 3 in this embodiment as well.
- Punching press may be used as a means for forming the slits 6. More specifically, the slits 6 can be formed through punching by inserting a grooved rod into the hollow pipe 3 and moving a punch toward the groove of the rod from the outside. The tip end of the hollow pipe 3 may be closed by crushing or squeezing deformation instead of screwing a stopper bolt 21.
- the outer circumferential surface of the radially expansive portion 7a is formed with wavy irregularities at a fine pitch.
- This embodiment is similar to the embodiment shown in FIG. 2(D) , but differs from the embodiment shown in FIG. 2(D) in that the irregularities are provided by forming a multiplicity of grooves on the radially expansive portion 7. Therefore, the projections of the irregularities does not provide resistance to insertion of the hollow pipe into the pre-formed hole 2. Nevertheless, the projections come into biting engagement with the pre-formed hole 2 when the radially expansive portion 7 bulges, thereby providing a high withdrawal resistance.
- two radially expansive portions 7 are formed as axially separated from each other.
- the two radially expansive portions 7 press against the pre-formed hole 2 as axially spaced from each other. Therefore, a very high withdrawal resistance may be expected.
- Three or more radially expansive portions 7 may be formed at positions that are axially separated from one another. Further, the plurality of radially expansive portions 7 may differ from each other in length.
- diametrically different balls 10 are used as the radially expanding action member.
- the group of the balls 10 can be caused to press against the inner surface of the radially expansive portion 7 in a distributed manner as much as possible, so that the plurality of sections divided by the slits 6 are easy to bulge individually.
- a multiplicity of (a plurality of) bowl-shaped elements 24 that overlap one another are used as the radially expanding action member.
- the outer circumference and inner circumference of the bowl-shaped element 24 are respectively formed into tapered surfaces 25 and 26 that are both inclined in the same direction.
- the inclination angle of the inner tapered surface 25 is smaller than the inclination angle of the outer tapered surface 26.
- a portion other than the central portion is divided by a plurality of (four) slits that extend radially. Therefore, the bowl-shaped elements 24 are bulgeable to increase its outer diameter.
- each of the bowl-shaped elements 24 deforms expansively, thereby causing the radially expansive portion 7 to bulge.
- the outer circumference of each of the bowl-shaped elements 24 is convexly curved in cross section to come into line contact with the radially expansive portion 7.
- the radially expanding action member comprises a group of discontinuous rings 27 each bent into an annular shape, and balls (steel balls) 28 each arranged between the adjacent rings 27.
- the rings 27 are formed by bending a wire having a circular cross section substantially into a circular form. However, since one end of the wire is not connected to the other end, the ring 27 deforms expansively under pressure from the balls 28.
- the radially expansive portion 7 can be expanded uniformly in the circumferential direction by the rings 27. Therefore, it is expected that the radially expansive portion 7 is prevented from coming into localized contact with the pre-formed hole 2, consequently providing a very high withdrawal resistance.
- a rod 19 is arranged between the bolt 9 and the balls 10. Therefore, the bolt 9 may be shortened, and the time needed for machining the female screw hole 8 can be reduced.
- a wavy element 30 that is bent into a zigzag manner in the axial direction is used as the radially expanding action member.
- the wavy element 30 is divided into four equal sections in the circumferential direction (or may be divided into three equal sections or five or more equal sections) . Therefore, when the wavy element 30 is pressed by the bolt 9, its outer diameter increases due to a reduction of its length, consequently causing the radially expansive portion 7 to bulge.
- a stopper rod 31 is provided in a portion surrounded by the wavy element 30. Due to the presence of this stopper rod 31, the wavy element 30 deforms to increase its outer diameter.
- the stopper rod 31 is integrally or separately formed on the bolt 9, and slides in a hole 32 formed in the tip end 3a of the hollow shaft 3 when the bolt 9 is screwed in. In this embodiment as well, the sections divided by the slits 6 can be bulged uniformly.
- FIG. 6 specifically shows an exemplary use of the expansion anchor shown in FIG. 3(A) .
- the expansion anchor is applied to a ceiling portion 1' of a tunnel, for example, and the fixing male screw 16 provided at the base end of the hollow shaft 3 is exposed downward from the ceiling surface.
- An upper piece 33a of a channel suspension fitting 33 is fixed to the ceiling surface using the nut 17, and a suspension bolt 34 is attached to the lower piece 33b of the suspension fitting 33.
- the suspension bolt 34 is used to suspend a ceiling panel or a ceiling frame.
- a socket bolt in which a hexagonal hole is formed in its head is used as the bolt 9 for expanding the radially expansive portion 7, and the head is exposed downward from the ceiling surface (a bolt with a polygonal head can also be used) . It is possible to determine, by rotating the bolt 9 with a torque wrench 35, whether or not the hollow shaft 3 retains an appropriate withdrawal resistance. In this case, when the torque wrench 35 indicates a predetermined value of measurement with the bolt 9 kept non-rotated, an appropriate withdrawal resistance is still retained, so that it is not necessary to take any specific countermeasure.
- the bolt 9 rotates before the measurement of the torque wrench 35 reaches the predetermined value, the biting force of the radially expansive portion 7 against the installation region 1 may have decreased. Therefore, the bolt 9 is rotated until the measurement of the torque wrench increases to the predetermined value.
- the provision of the fixing male screw 16 at the base end of the hollow shaft 3 enables the maintenance of the expansion anchor (adjustment of withdrawal resistance) without removing the suspension fitting 33. Therefore, the maintenance can be performed easily and efficiently.
- a bolt 9 for expanding the radially expansive portion 7 use may be made of a hexagonal-socket bolt having no enlarged head or a bolt with a quadrangular head the circumcircle of which has a diameter equal to or smaller than the outer diameter of the screw thread.
- the use of such a bolt is advantageous in that it does not affect screwing of the nut 17.
- FIG. 7 shows the test.
- FIGS. 7(A) and 7(B) show samples that were used in the test. The samples were similar to the first embodiment.
- the outer diameter was 10 mm
- the entire length was 60 mm
- the inner diameter of the hollow shaft was about 6 mm
- a 8-mm bolt was used as the bolt 9 (the inner diameter of the pre-formed hole of a 8-mm female screw corresponded to the inner diameter of the hollow shaft).
- the radially expansive portion 7 had a length of about 25 mm, the hollow shaft 3 had a constant diameter over the entire length thereof, and the tip end was closed.
- a portion of about 8 mm at the tip end was squeezed, and therefore, the radially expansive portion 7 was shorter than that of the A type.
- a plurality of diametrically different steel balls were used as the radially expanding action member. More specifically, one ball having an outer diameter of 6 mm, three balls having an outer diameter of 4.5 mm, three balls having an outer diameter of 5 mm, and one ball having an outer diameter of 6 mm were arranged in this order from the bolt 9 side.
- a conventional product (commercially available product) C shown in FIG. 7 (C) was used as a comparative example.
- this conventional product C the entire length and outer diameter were the same as those of the two samples (60 mm, 10 mm), and four slits C2 were formed in the tip end side of a hollow shaft C1 to be open at the tip end face.
- a portion in which the slits were formed was an radially expansive portion C3 to be expanded into a flaring manner.
- a pin C4 was inserted into the hollow shaft C1 from the base end.
- the pin C4 had a tapering tip end. When the pin C4 was hit into the radially expansive portion C3, the radially expansive portion C3 was expanded. Therefore, the withdrawal resistance of this comparative example C became constant.
- FIG. 7(E) shows the results. Specifically, in FIG. 7(E) , the horizontal axis F indicates the screwing torque of the bolt 9, whereas the vertical axis S indicates the withdrawal resistance.
- a concrete block was used as a target product serving as the installation region.
- A1 was an A type in which the outer circumference of the radially expansive portion 7 was knurled, and A2 was an noraml A type in which the outer circumference of the radially expansive portion 7 was smooth.
- B1 was a B type in which the outer circumference of the radially expansive portion 7 was knurled, whereas B2 was a normal B type in which the outer circumference of the radially expansive portion 7 was smooth. Knurling was performed in an inclined lattice pattern with a fine pitch.
- the graph in FIG. 7(E) clearly shows that the withdrawal resistance increases with an increase in the screwing torque of the bolt 9. It can be understood from these results that the withdrawal strength can be controlled to a desired level by controlling the torque of the bolt 9. It can also be understood that the withdrawal resistance increased due to knurling, and there was no significant difference between the A type and the B type.
- the graph in FIG. 7(D) shows relationship between the amount of shift of the expansion anchor and the withdrawal resistance when the expansion anchor was pulled using a drawing test machine. Specifically, in the graph in FIG. 7(D) , the horizontal axis indicates an axial shift, while the vertical axis indicates a withdrawal resistance.
- the test used an A1 type bolt 9 that was screwed at 20 KNm, an A1 type bolt 9 that was screwed at 8 KNm, and a comparative example C.
- the withdrawal resistance of the anchor had a peak value, and the withdrawal resistance decreased with an increase of drawn amount after exceeding the peak value. Such a result was predictable.
- a multiplicity of diametrically larger balls having substantially the same diameter as the inner diameter of the radially expansive portion 7 are arranged, and a plurality of (e.g., four to six) diametrically smaller balls are arranged between adjacent ones of the diametrically larger balls generally at an axial center of the radially expansive portion 7.
- a plurality of diametrically smaller balls are arranged between adjacent ones of the diametrically larger balls generally at an axial center of the radially expansive portion 7.
- auxiliary members 36 are inserted into the radially expansive portion 7, so that the radially expansive portion 7 is caused to bulge via the auxiliary members 36.
- the auxiliary members 36 are arranged in corresponding relation to and without any circumferential shift from the sections of the radially expansive portion 7 divided by the slits, and outward protrusions 36a are provided at axially shifted positions on the auxiliary members 36 respectively.
- the auxiliary members 36 have such a strength that they do not easily deform. When the group of the balls 10 are pushed by a bolt, the auxiliary members 36 are radially pushed, and the respective sections of the radially expansive portion 7 are bulged due to the protrusions 36a of the auxiliary members 36.
- At least the radially expansive portion 7 is formed in an elliptic shape, and four slits 6 are formed to circumferentially separate thin portions and thick portions.
- the thin portions are concentratively deformed, so that the radially expansive portion 7 can be easily bulged in a symmetrical manner.
- the balls come into contact with the thin portions at axially separated positions. Therefore, even when the radially expansive portion 7 is bulged in a symmetrical manner, the bulges are shifted in the axis direction.
- the slits 6 are formed at uneven intervals in the radially expansive portion 7 which is perfectly circular, thereby providing easily deformable zones in the radially expansive portion 7. In this case as well, so that the radially expansive portion 7 can be easily bulged in a symmetrical manner.
- two pins 37m 38 are inserted into the hollow shaft 3 at a forward position and a rearward position, respectively, and a plurality of balls 10 are arranged between the two pins.
- the pins 37, 38 are formed into a bullet shape having a tapering tip end, and they are arranged such that their tip ends face each other. Therefore, when the rear side pin 38 is pushed using a bolt, the balls 10 are rearranged into a circumferential array due to the clamping action of the pins 37, 38 while moving outward orthogonally to the axis in such an array. Accordingly, the radially expansive portion 7 can be made to bulge accurately at a predetermined position.
- the number of the balls 10 may be set to be three to ten, for example.
- the bolt 9 cannot be further screwed, consequently preventing the radially expansive portion 7 from bulging excessively.
- the maximum screwing torque of the bolt 9 can also be controlled.
- the tip ends of the pins 37, 38 may be conical or frustoconical, or may be curved to be outwardly concave as opposed to the illustrated embodiment.
- FIG. 8(G) and the features shown in FIG. 8(E) or 8(F) may be combined for causing the radially expansive portion 7 to readily bulge at two opposite positions that are separated by 180 degrees. It is also possible to use three pins and arrange balls 10 between the adjacent pins. In this case, two radially expansive portions 7 are provided as axially separated from each other, so that the two radially expansive portions 7 are separaly expansive using the balls. Therefore, the embodiment shown in FIG. 8(A) may be realized easily. Use may be made of four or more pins for bulging at three or more axially different portions.
- annular groove 39 is formed in the outer circumferential surface of the pin 38 at an rear end portion, and an O-ring (or a rubber ring) 40, which is an example of a removal restraining means, is fitted in the annular groove 39.
- the O-ring 40 is fitted into the hollow shaft 3 in an elastically deformed state, so that it does not remove easily. Therefore, the balls 10 are prevented from falling out due to careless handling during assembly. Even when the bolt 0 is removed after the installation, the pins 37, 38 and the balls 10 do not fall out.
- the present invention may provide various other embodiments in addition to the above-described embodiments.
- the radially expanding action member is not limited to those shown in the drawings, and any radially expanding action member may be used as long as it is capable of pressing against the radially expansive portion from the inside in response to a pushing action of the bolt. Therefore, a wire rod bent into a bow shape or a helically wound member such as a coil spring may also be used. When a helically wound member having a triangular or trapezoidal cross section is used, it is capable of providing a high radially expanding action.
- the outer circumferential surface of the radially expansive portion may be provided with a multiplicity of projections.
- a member such as a suspension fitting may be welded in advance to the hollow shaft.
- the hollow shaft, the radially expanding action member and the bolt may be made of a resin if there is no problem with respect to thermal resistance.
- the radially expansive portion may also be formed by replacing the slits with a multiplicity of holes or thin-walled sections.
- a plug made of a soft material such as rubber, for example may be inserted into the hollow shaft.
- the plug is crushed by the bolt, so that it does not pose any problem with respect to the function of pressing against the balls.
- the plug is held inside the hollow shaft, so that the radially expanding action member such as balls can be prevented from falling out.
- a metal plug formed on its outer circumference with an annular groove for fitting an elastic ring such as an O-ring.
- an elastic ring such as an O-ring.
- the radially expanding action member such as balls is pressed by the bolt via the plug.
- the present invention can be practically embodied as an expansion anchor. Therefore, the present invention is industrially applicable.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Dowels (AREA)
- Joining Of Building Structures In Genera (AREA)
Abstract
Description
- The present invention relates to an expansion anchor of the type in which a portion of a hollow shaft is bulged by screwing of a bolt.
- Expansion anchors are used to attach various members such as fittings to stony structures made of concrete or the like, as in the case where various members are suspended from the inner surface of a tunnel, for example. There are various types of expansion anchors. In general, the tip end of a hollow shaft (anchor body) is divided by a plurality of circumferentially separated longitudinal slits to provide an radially expansive portion (expansion portion), and the radially expansive portion is bulged utilizing a wedging action caused by screwing of a bolt.
- There is also an expansion anchor of the type that utilizes, instead of a bolt, a pin with a tapering tip portion having a progressively decreasing diameter toward the tip end. In this case, the pin is impacted with a hammer for insertion into the hollow shaft.
- There is also a proposal in which an anchor body is expanded indirectly instead of being directly expanded with a bolt. In one example shown in
Patent Document 1, a ball made of metal is inserted into a radially expansive portion for bulging the radially expansive portion due to an expanding action caused by the ball.Patent Document 2 also discloses a similar configuration.Patent Documents -
- Patent Document 1:
JP 2004-218421A - Patent Document 2: Microfilm of
JP H4-272019U - Patent Document 3:
Japanese Registered Utility Model No. 3007126 - Patent Document 4: Microfilm of
JP S52-6970U - As described above, the expansion anchors disclosed in the patent documents and the hit-type expansion anchors provide a withdrawal resistance by expanding the radially expansive portion located at the tip end of the hollow shaft into a flaring shape and pressing the radially expansive portion against a pre-formed hole. However, in reality, there is a limit on how much the withdrawal resistance of the conventional expansion anchors can be increased (in the case of the hit-type expansion anchors, the withdrawal resistance is fixed theoretically).
- A troublesome problem regarding an expansion anchor is a phenomenon called cone-type failure wherein a portion of concrete centered around the expansion anchor at the installation region comes off in the form of a cone. Such a cone-type failure occurs due to the expansion of the radially expansive portion of the anchor. Therefore, in order to prevent the cone-type failure, an expansion anchor is designed in a manner such that the radially expansive portion thereof do not expand excessively, which is one of the detrimental factors in enhancing the withdrawal resistance.
- A more troublesome problem is that, when an anchor is engaged into the ceiling of a concrete tunnel for example, the weight of a workpiece acts as a downward load on the expansion anchor, and this downward load may cause cone-type failure. In other words, even if there appears no problem at the time of installation, a cone-type failure occurs as a delayed failure upon lapse of time.
- The present invention, which has been conceived in light of the aforementioned circumstances, provides an expansion anchor that keeps a high withdrawal resistance while also providing a high functionality for preventing a cone-type failure.
- The present invention includes various structural features. Typical aspects thereof are identified as first to fifth inventions.
- The first invention is a generic invention which provides an expansion anchor includes a hollow shaft to be inserted, from a tip end thereof, into a pre-formed hole formed in an installation region, and a bolt to be screwed into the hollow shaft from outside the installation region, wherein the hollow shaft is formed with a radially expansive portion, that is weakened to be bulgeable, at a portion of the hollow shaft within the pre-formed hole and short of the tip end of the hollow shaft, and the hollow shaft is internally provided with a radially expanding action member that pushes the radially expansive portion radially outward in response to pushing action caused by screwing of the bolt into the hollow shaft.
- According to the present invention, the hollow shaft does not need to be open at both ends if at least its base end (to be located outside of the installation region) is open. Therefore, the tip end to be inserted into the pre-formed hole may have a solid structure. Further, according to the present invention, a plurality of radially expansive portions can be provided. These are the major features of the present invention.
- In general, the expansion anchor may usually have a perfect circular shape, but its shape is not necessarily limited to a perfect circle in the present invention. For example, the present invention may comprise a structure in which the entire hollow shaft or only the radially expansive portion is formed in a non-perfect circle such as an ellipse or a polygon. Examples of a non-perfect circular shape also include a shape that basically follows a perfect circle but has two flat faces which are parallel to each other. The pre-formed hole is generally formed in a perfect circular shape at the installation region using a rotating drill. However, when the hollow shaft has a non-perfect circular shape, the pre-formed hole may be processed into a non-perfect circle corresponding to the shape of the hollow shaft.
- The second invention is a development of the first invention in which the radially expansive portion of the hollow shaft is formed with a plurality of axially elongated slits that are circumferentially spaced from each other. In other words, according to the second invention, a portion of the hollow shaft in which the slits are formed serves as a radially expansive portion. The number of the slits may be selected depending on the outer diameter or thickness of the hollow shaft. In general, three to six slits may be usually formed. The slits in a group may be arranged at circumferentially regular or irregular intervals.
- The third invention is a development of the first invention or second invention in which the radially expanding action member includes a multiplicity of metal balls, and the radially expansive portion is allowed to bulgingly deform due to the balls moving radially outward in group in response to a push from the bolt. Regarding the balls in the group may be entirely equal in diameter, or they may include a plurality of diametrically different balls.
- The fourth invention is a development of the third invention. According to the third invention, the radially expansive portion has an axial length that is at least twice an outer diameter of the hollow shaft. The fourth invention may also be regarded as a development of the first invention or second invention. One major feature of the present invention is that the length of the radially expansive portion can be set to be extended.
- A member such as a fitting may be attached to the expansion anchor. The fifth invention is an implementation in this regard. More specifically, the fifth invention is based on the third invention, wherein wherein the hollow shaft is configured such that the other end is exposed outside the installation region, at least a portion of the hollow shaft that is exposed outside of the installation region is formed with fixing threads, and the fixing male screw is engageable with a nut for mounting another member. The fifth invention may also be regarded as a development of the first, second invention, or fourth invention.
- According to the present invention, the radially expansive portion is located at a position short of the tip end of the hollow shaft. Therefore, the radially expansive portion does not expand into a flaring form but bulges expansively in a direction orthogonal to the axis. This bulging portion comes into biting engagement with the pre-formed hole at the installation region (made of concrete), consequently providing a resistance against withdrawal.
- According to the present invention, even if the radially expansive portion comes into deep biting engagement with the installation region, such an engagement does not lead to much increase of the compressive force with which the radially expansive portion presses against the installation region in a direction orthogonal to the axis. The reason for this seems to be that the bulging portion engages with the installation region in a biting manner. Accordingly, it is possible to provide a high withdrawal resistance while preventing a cone-type failure.
- One feature of the present invention resides in that the length of the radially expansive portion can be increased. Thus, the radially expansive portion having an increased length can come into deep biting engagement with the installation region, thereby contributing greatly to an increase in withdrawal resistance (namely, fastening strength).
- Due to the above-noted features of according to the present invention, the expansion anchor is particularly useful as a fastening tool to suspend a member from a concrete ceiling of a tunnel or building. Furthermore, according to the present invention, when the hooking force of the radially expansive portion reduces due to a timewise damage of the installation region for example, the withdrawal resistance may be restored by screwing the bolt to expand the radially expansive portion. Therefore, it is easy to adjust the torque to keep the withdrawal resistance at an appropriate value. In the case where the bolt has slided down, it is preferable to expand the radially expansive portion again after pushing the bolt back to the original depth.
- In the expansion anchor according to the present invention, since the radially expanding action member can be easily retreated by screwing back the bolt, it is easy to pull out the expansion anchor, which has been once attached, against the elastic force of the radially expansive portion. Accordingly, it is also easy to remove an unnecessary anchor and replace it with a new one.
- The slits formed according to the second invention as a means for forming the radially expansive portion is preferable because this enables the radially expansive portion to bulge in a reliable manner. Moreover, when the radially expansive portion is divided by the slits into a plurality of circumferentially separated sections, a specific one or ones of the sections are more likely to bulge for more readily coming into biting engagement with the installation region to provide better hooking to the installation region. Accordingly, it is possible to provide a high fastening strength can be reliably obtained while preventing cone-type failure.
- Metal balls (particularly steel balls) are widely used in various fields such as bearings, and various types of metal balls are commercially available. Therefore, when the metal balls are used as the radially expanding action member as set forth in
claim 3, it is possible to suppress the manufacturing cost due to ready availability of metal balls requiring no dedicated manufacturing apparatus. - Furthermore, when the metal balls are used as the radially expanding action member, the metal balls come into point contact with the radially expansive portion from the inside, so that the entire circumference of the radially expansive portion is not pressed uniformly. Instead, only specific circumferential positions of the radially expansive portion are pressed outward by the metal balls. As a result, the area of engagement of the radially expansive portion with the installation region is reduced, so that the radially expansive portion can easily come into biting engage with the installation region. In other words, the radially expansive portion can easily come into deep engagement with the installation region in the manner of biting into the installation region. In this way, it possible to provide a high hooking force while suppressing the compressive force against the installation region.
- Therefore, the metal balls as the radially expanding action member is advantageous in providing a high fastening strength without causing cone-type failure.
- The length (axial length) of the radially expansive portion may be selected depending on the required withdrawal resistance. When the radially expansive portion has an axial length that is at least twice an outer diameter of the hollow shaft as in the fourth invention, the radially expansive portion can be bulged reliably, so that a high withdrawal resistance (fastening strength) can be secured more reliably.
- In the case of a suspending expansion anchor for use on the ceiling of a tunnel for example, the maintenance of a predetermined withdrawal resistance is a very important factor. Therefore, the magnitude of the withdrawal resistance is checked regularly or as needed, and the withdrawal resistance, having dropped, should be restored to a preset value. A checking operation may be performed by rotating the bolt using a torque wrench. However, if a suspended member has to be removed every time the bolt is rotated using a torque wrench, the checking operation becomes troublesome.
- By contrast, if the fifth invention is employed, the head of the bolt pressing the radially expanding action member can be kept exposed outside of the installation region, so that the bolt can be rotated using a torque wrench while a member such as a ceiling panel or a ceiling frame is kept suspended by the expansion anchor. Accordingly, a maintenance operation can be performed very easily for checking whether or not the withdrawal resistance of the expansion anchor is kept at a predetermined value and restoring the withdrawal resistance which has dropped.
- In the maintenance operation, it is possible to try to rotate the bolt using a power-assisted wrench with a torque limiter (or a clutch) instead of rotating the bolt using a torque wrench. In this case, when the withdrawal resistance has decreased, the bolt rotates, and when a predetermined withdrawal resistance is kept, the bolt does not rotate. Therefore, the operating efficiency is very high.
-
-
FIG. 1(A) is a sectional side view of a first embodiment,FIG. 1(B) is a sectional view taken along line B-B inFIG. 1(A), FIG. 1(C) is a sectional view taken along line C-C inFIG. 1(A), FIG. 1 (C') is a sectional view of another example,FIG. 1(D) is a sectional view taken along line D-D inFIG. 1(A), FIG. 1(E) is a view showing a radially expanded state, andFIG. 1(B) is a view showing a state in which a member has been attached. -
FIG. 2(A) is a sectional side view of a second embodiment,FIG. 2 (B) is a side view of a third embodiment,FIG. 2(C) is a side view of a fourth embodiment, andFIG. 2(D) is a side view of a fifth embodiment. -
FIG. 3 (A) is a partially cutaway side view of a sixth embodiment,FIG. 3(B) is apartial side view of a seventh embodiment,FIG. 3 (C) is a partially cutaway side view of a eighth embodiment, -
FIG. 3 (D) is a sectional view taken along line D-D inFIG. 3(C), and FIG. 3(E) is a partially cutaway side view of a ninth embodiment. -
FIG. 4(A) is a sectional side view of a tenth embodiment,FIG. 4(B) is a partially cutaway side view of an eleventh embodiment,FIG. 4 (C) is a sectional side view of a twelfth embodiment, andFIG. 4 (D) is a sectional side view of a thirteenth embodiment. -
FIG. 5(A) is a sectional side view of a fourteenth embodiment,FIG. 5(B) is a sectional side view of a fifteenth embodiment,FIG. 5(C) is a sectional view taken along line C-C inFIG. 5(B), FIG. 5(D) is a sectional side view of a sixteenth embodiment,FIG. 5(E) is a sectional side view of main portions of a seventeenth embodiment, andFIG. 5(F) is a sectional view taken along line F-F inFIG. 5(E) . -
FIG. 6 is a view showing a use example of the expansion anchor shown inFIG. 3(A) . -
FIG. 7 illustrates a test for examining the advantageous effects of the present invention. -
FIGS. 8(A) to 8(C) are views showing preferred bulging states of a radially expansive portion,FIG. 8(D) is a sectional view of an eighteenth embodiment,FIG. 8(E) is a sectional view of a nineteenth embodiment,FIG. 8(F) is a sectional view of a twentieth embodiment, and FIG. 8(G) is a sectional view of a twenty-first embodiment. - Next, embodiments of the present invention will be described based on the drawings. First, description is made as to a first embodiment shown in
FIG. 1 . An expansion anchor includes ahollow shaft 3 to be inserted into apre-formed hole 2 in aninstallation region 1 made of concrete. In thehollow shaft 3, an end that will enter thepre-formed hole 2 is defined as atip end 3a, and an opposite end is defined as abase end 3b. Thebase end 3b of thehollow shaft 3 is provided with a flange (or head) 4 having a hexagonal shape or a circular shape. - The
hollow shaft 3 is formed with ahole 5 over the entire length thereof, and thehole 5 has a small-diameter portion 5a within a certain range from thetip end 3a. Thetip end 3a may have a solid structure in which the small-diameter portion 5a of thehole 5 is eliminated. Thehole 5 may have a constant diameter over the entire length thereof, and thetip end 3a is closed with a plug. Thehollow shaft 3 may also be formed by stretching a hollow coil pipe with a small-diameter hole. In this case, the inner diameter of the material coil pipe remains as the diameter of the small-diameter portion 5a, whereas the other portion of the hollow shaft is diametrically enlarged by drilling or the like. The material of thehollow shaft 3 may be selected as needed. When high durability and rust-resistance are required as in the case of anchors for tunnels, it is preferable to use a hollow shaft made of stainless steel. Steel that has undergone surface treatment such as plating is also preferable. - Within a certain range of the
hollow shaft 3 short of thetip end 3a, there are formed four axiallyelongated slits 6 at regular circumferential intervals. The portion of the hollow shaft in which theslits 6 are formed serves as an radiallyexpansive portion 7 that is bulgeable in a direction orthogonal to the axis. Therefore, theslits 6 do not extend into thetip end 3a of thehollow shaft 3. Further, theslits 6 communicate with the inside and outside of thehollow shaft 3. Theslits 6 may be machined using a milling cutter, for example. - The number of the
slits 6 can be selected as desired. In the example shown inFIG. 1 (C'), sixslits 6 are formed. The axial length of the radiallyexpansive portion 7 is set to be about twice the outer diameter of thehollow shaft 3. When the radiallyexpansive portion 7 has a small thickness, the radiallyexpansive portion 7 can be easily deformed even if its length is shorter than twice the outer diameter of thehollow shaft 3. - The
hole 5 of thehollow shaft 3 is formed with afemale screw 8 in a portion (toward thebase end 3b) short of the radiallyexpansive portion 7, and a hexagonal-socket bolt 9 is screwed into thefemale screw 8 from the outside (thefemale screw 8 may extend into the radially expansive portion 7). A multiplicity of metal balls (steel balls) 10, as an example of radially expanding action member, are accommodated between thebolt 9 and thetip end 3a. The outer diameters of theballs 10 are set to be slightly smaller than the inner diameter of thehole 5, and in the illustrated example, theballs 10 have an equal outer diameter. It will be appreciated that the outer diameter of theballs 10 may be set to be substantially equal to the inner diameter of thehole 5. - When the
bolt 9 does not press theballs 10, part of theballs 10 is located on the base end side with respect to the radiallyexpansive portion 7. The outer diameter of thehollow shaft 3 and the inner diameter of thehole 5 may be set as desired. In other words, the thickness of thehollow shaft 3 may be set as desired. - A method of using the expansion anchor is similar to a conventional method. As shown in
FIG. 1(E) , thehollow shaft 3 is fitted into thepre-formed hole 2 in theinstallation region 1, and then thebolt 9 is screwed thereinto using ahexagonal bit 11. This causes the group ofballs 9 to be moved in a chain reaction manner. Theadjacent balls 10 are in contact with each other, and therefore, theballs 10 also tend to move radially of thehollow shaft 3. As a result, the radiallyexpansive portion 7 deforms expansively over a long range and engages with thepre-formed hole 2 in theinstallation region 1. - The radially
expansive portion 7 is shown to expand into a plateau shape by solid lines inFIGS. 1(E) and 1(F) . In reality, however, the radiallyexpansive portion 7 is more likely to bulge in a mountain-like shape (or a bow shape) as indicated by a chain line inFIG. 1(E) because theballs 10 pressing against one another act such that theballs 10 located at weaker portions are pressed more strongly. More specifically, although theballs 10 come into point contact with the radiallyexpansive portion 7, theball 10 that comes into contact with the weakest portion of the radiallyexpansive portion 7 is most strongly pressed by theother balls 10, so that the radiallyexpansive portion 7 is deformed in a mountain-like shape. When the length of the radiallyexpansive portion 7 is reduced, the radiallyexpansive portion 7 inevitably bulges in a mountain-like shape or a bow shape. - The radially
expansive portion 7 is divided into a plurality of sections by theslits 6. It is more likely that the weakest one of these sections is concentratively bulged rather than all sections bulging uniformly. Therefore, in general, bulging may occur only at one circumferential position of the radiallyexpansive portion 7. - Incidentally, the tip end of a conventional expansion anchor expands in a flaring manner. Such an expansion state is schematically shown by a chain line in
FIG. 1(F) , and a radially expansive portion is denoted by areference numeral 7a. In this case, the leading end of the radially expansive portion 7' moves as indicated by anarrow 7b, and a pressing force (compressive load) acts on theinstallation region 1 made of concrete as indicated by thearrow 7b. In this state, a boundary may be generated in theinstallation region 1 made of concrete between a portion pressed strongly by the radiallyexpansive portion 7a and a portion not so pressed. Thus, it is speculated that a sliding phenomenon occurs along the boundary, resulting in cone-type failure. Furthermore, the radiallyexpansive portion 7a applies a pressing force in thedirection 7b which is inclined relative to the anchor axis, and it is also speculated that the boundary is likely to form a conical surface, which may promote cone-type failure. - According to the illustrated embodiment of the present invention, on the other hand, the radially
expansive portion 7 is deformed into a mountain-like shape or the like. It is thus speculated that the radiallyexpansive portion 7 engages with theinstallation region 1 while biting into the structural material instead of strongly pressing against theinstallation region 1. In other words, it is considered that the expansion anchor according to the embodiment of the present invention is hooked to the pre-formed hole due to biting rather than staying in the pre-formed hole due to friction. This makes it possible to achieve a high withdrawal resistance while preventing cone-type failure. - Moreover, according to the embodiment of the present invention, the radially
expansive portion 7 bulges in a direction orthogonal to the axis of thehollow shaft 3, so that a boundary may not be formed in theinstallation region 1 between a portion subjected to a strong pressing force and a portion not subjected to a strong pressing force. Instead, the pressing force (compressive stress) acting on theinstallation region 1 changes gradually in the axial direction, thereby contributing greatly to the prevention of cone-type failure. - The
hexagonal bit 11 is attached to a torque wrench. The pushing force of the radiallyexpansive portion 7 against thepre-formed hole 2 is proportional to the screwing torque of thebolt 9. Therefore, when a predetermined screwing torque is reached by screwing thebolt 9 with a torque wrench, rotation of the bolt is stopped. Thebolt 9 has deeply entered into thefemale screw hole 8 when the radiallyexpansive portion 7 is bulged. Therefore, amember 13 can be fixed to the base end surface of thehollow shaft 3 by screwing afastening bolt 12 into thefemale screw hole 8. Accordingly, a state has to be achieved in which thebolt 9 enters entirely into thefemale screw hole 8 to allow another bolt to be further screwed into thefemale screw hole 8 from the outside. - The use mode of the expansion anchor may be set as desired depending on the conditions of the installation region. When the
pre-formed hole 2 is formed in the ceiling surface of a structure, it is sufficient that a suspension bolt is screwed into thehollow shaft 3 from below, and various members such as a ceiling panel is suspended by the suspension bolt (this example will be described later). It is sufficient that the length of the radiallyexpansive portion 7 is set as desired depending on the length of thehollow shaft 3, required withdrawal resistance, or the like. - Next, second to fifth embodiments shown in
FIG. 2 will be described. According to the second embodiment shown inFIG. 2 (A) , thebase end 3a of thehollow shaft 3 is provided with no flange, but the second embodiment has otherwise the same structure as the first embodiment. The radiallyexpansive portion 7 is shown to bulge in a trapezoidal shape. In reality, however, the radiallyexpansive portion 7 is more likely to bulge in a mountain-like shape as indicated by the chain line inFIG. 1(E) . - The third embodiment shown in
FIG. 2 (B) and the fourth embodiment shown inFIG. 2(C) share a common structure in which the outer circumference of thehollow shaft 3 is formed with an engagingmale screw 15 for engagement with the pre-formed hole. In the example shown inFIG. 2(B) , aflange 4 is formed at thebase end 3b of thehollow shaft 3, whereas a straight structure of the hollow shaft without aflange 4 is obtained in the example shown inFIG. 2(C) . The engagingmale screw 15 may have a pitch that is plural times larger than the thread width for facilitating the inserting engagement into thepre-formed hole 2 in theinstallation region 1. A plurality of threads having different heights may also be formed. - In the case where the engaging
male screw 15 is formed, when theflange 4 as shown inFIG. 2(B) is formed in a polygonal shape such as a hexagonal shape that can be rotated using a spanner (wrench), thehollow shaft 3 can be easily screwed into thepre-formed hole 2. - In the illustrated embodiment, the engaging
male screw 15 is formed only up to a position short of the radiallyexpansive portion 7. However, the engagingmale screw 15 may be formed to extend also over the entirety of the radiallyexpansive portion 7. The engagingmale screw 15 formed to extend over the radiallyexpansive portion 7 is expected to remarkably improve the withdrawal resistance because the engagingmale screw 15 comes into strong biting engagement with thepre-formed hole 2 due to bulging of the radiallyexpansive portion 7. - In the fifth embodiment shown in
FIG. 2(D) , a multiplicity ofannular projections 16 are formed on the radiallyexpansive portion 7. Eachannular projection 16 has a cross-sectional shape of a right-angled triangle with its inclined surface oriented toward thetip end 3a, consequently providing a high withdrawal resistance. The annular projections 16A may be replaced with a spiral projection. Alternatively, the outer circumference of the radiallyexpansive portion 7 may be knurled. - Next, sixth to ninth embodiments shown in
FIG. 3 will be described. In the sixth embodiment shown inFIG. 3(A) , a fixingmale screw 16 for screwing engagement with anut 17 is formed within a certain range on the base end side of thehollow shaft 3. Therefore, the fixing male screw 18 serves as a metric screw thread. - In this embodiment, a
member 13 is formed with anattachment hole 19 in which the fixingmale screw portion 16 is fitted, and themember 13 is pressed against and fixed to the surface of theinstallation region 1 using thenut 17. It is unnecessary to insert thebolt 9 entirely into thehollow shaft 3, so that a bolt with a head can be used as thebolt 9. Moreover, the radiallyexpansive portion 7 may be made to bulge in response to operating thebolt 9 while themember 13 is fixed. - The seventh embodiment shown in
FIG.3 (B) is a modified example of the sixth embodiment. In this embodiment, aflange 4 is provided on thehollow shaft 3, a fixingmale screw 16 is formed outwardly from theflange 4, and an engagingmale screw 15 is formed on a side opposite to the fixingmale screw 16. Theflange 4 may preferably have a polygonal shape such as a hexagonal shape. - In the eighth embodiment shown in
FIGS. 3(C) and 3(D) , an engagingmale screw 15 is formed on the outer circumference of thehollow shaft 3, and an engaginghole 20 for fitting engagement with apolygonal bit 11 having a hexagonal shape or the like is formed at the base end of thehollow shaft 3. Therefore, aflange 4 may be unnecessary. - In the ninth embodiment shown in
FIG. 3(E) , thebolt 9 for bulging the radiallyexpansive portion 7a has a hexagonal socket, and thebolt 9 is set to be exposed to the outside of thehollow shaft 3 even in the state where the radiallyexpansive portion 7 is bulged. Themember 13 is fitted over thebolt 9 and fixed thereto using anut 17. Therefore, in this embodiment, thebolt 9 for bulging the radiallyexpansive portion 7 is used to attach (fix) themember 13. Further, a rotational operation (torque adjustment) of thebolt 9 can be easily performed by loosening thenut 17. Thenut 17 also serves to prevent thebolt 9 from loosening. - In the tenth embodiment shown in
FIG. 4(A) , ahole 5 is formed in thehollow shaft 3 over the entire length thereof, and afemale screw 8 is formed in thehole 5 over the entire length thereof, and astopper bolt 21 is screwed into the hollow shaft from the tip end thereof. In this embodiment, use may be made of a pipe for forming thehollow shaft 3, thus contributing to a cost reduction.Female screws 8 may be formed only on two sides flanking the radiallyexpansive portion 7. Also shown is amilling cutter 22 that is machining theslits 6. Although themilling cutter 22 is shown to be moved in the figure, thehollow shaft 3 may be moved instead. A fixingmale screw 16 such as shown inFIG. 3 (A) may be formed at thebase end 3b of thehollow shaft 3 in this embodiment as well. - Punching press may be used as a means for forming the
slits 6. More specifically, theslits 6 can be formed through punching by inserting a grooved rod into thehollow pipe 3 and moving a punch toward the groove of the rod from the outside. The tip end of thehollow pipe 3 may be closed by crushing or squeezing deformation instead of screwing astopper bolt 21. - In the eleventh embodiment shown in
FIG. 4(B) , the outer circumferential surface of the radiallyexpansive portion 7a is formed with wavy irregularities at a fine pitch. This embodiment is similar to the embodiment shown inFIG. 2(D) , but differs from the embodiment shown inFIG. 2(D) in that the irregularities are provided by forming a multiplicity of grooves on the radiallyexpansive portion 7. Therefore, the projections of the irregularities does not provide resistance to insertion of the hollow pipe into thepre-formed hole 2. Nevertheless, the projections come into biting engagement with thepre-formed hole 2 when the radiallyexpansive portion 7 bulges, thereby providing a high withdrawal resistance. - In the twelfth embodiment shown in
FIG. 4(C) , two radiallyexpansive portions 7 are formed as axially separated from each other. With this configuration, the two radiallyexpansive portions 7 press against thepre-formed hole 2 as axially spaced from each other. Therefore, a very high withdrawal resistance may be expected. Three or more radiallyexpansive portions 7 may be formed at positions that are axially separated from one another. Further, the plurality of radiallyexpansive portions 7 may differ from each other in length. - In the thirteenth embodiment shown in
FIG. 4(D) , diametricallydifferent balls 10 are used as the radially expanding action member. In this embodiment, the group of theballs 10 can be caused to press against the inner surface of the radiallyexpansive portion 7 in a distributed manner as much as possible, so that the plurality of sections divided by theslits 6 are easy to bulge individually. - Next, fourteenth to seventeenth embodiments shown in
FIG. 5 will be described. In the fourteenth embodiment shown inFIG. 5(A) , a multiplicity of (a plurality of) bowl-shapedelements 24 that overlap one another are used as the radially expanding action member. The outer circumference and inner circumference of the bowl-shapedelement 24 are respectively formed into taperedsurfaces surface 25 is smaller than the inclination angle of the outer taperedsurface 26. A portion other than the central portion is divided by a plurality of (four) slits that extend radially. Therefore, the bowl-shapedelements 24 are bulgeable to increase its outer diameter. - When the group of the bowl-shaped
elements 24 are pressed toward thetip end 3a of thehollow shaft 3 using thebolt 9, each of the bowl-shapedelements 24 deforms expansively, thereby causing the radiallyexpansive portion 7 to bulge. The outer circumference of each of the bowl-shapedelements 24 is convexly curved in cross section to come into line contact with the radiallyexpansive portion 7. - In the fifteenth embodiment shown in
FIGS. 5(B) and 5(C) , the radially expanding action member comprises a group ofdiscontinuous rings 27 each bent into an annular shape, and balls (steel balls) 28 each arranged between the adjacent rings 27. Therings 27 are formed by bending a wire having a circular cross section substantially into a circular form. However, since one end of the wire is not connected to the other end, thering 27 deforms expansively under pressure from theballs 28. - In this embodiment, the radially
expansive portion 7 can be expanded uniformly in the circumferential direction by therings 27. Therefore, it is expected that the radiallyexpansive portion 7 is prevented from coming into localized contact with thepre-formed hole 2, consequently providing a very high withdrawal resistance. - In the sixteenth embodiment shown in
FIG. 5(D) , arod 19 is arranged between thebolt 9 and theballs 10. Therefore, thebolt 9 may be shortened, and the time needed for machining thefemale screw hole 8 can be reduced. - In the seventeenth embodiment shown in
FIGS. 5(E) and 5(F) , awavy element 30 that is bent into a zigzag manner in the axial direction is used as the radially expanding action member. Thewavy element 30 is divided into four equal sections in the circumferential direction (or may be divided into three equal sections or five or more equal sections) . Therefore, when thewavy element 30 is pressed by thebolt 9, its outer diameter increases due to a reduction of its length, consequently causing the radiallyexpansive portion 7 to bulge. - A
stopper rod 31 is provided in a portion surrounded by thewavy element 30. Due to the presence of thisstopper rod 31, thewavy element 30 deforms to increase its outer diameter. Thestopper rod 31 is integrally or separately formed on thebolt 9, and slides in ahole 32 formed in thetip end 3a of thehollow shaft 3 when thebolt 9 is screwed in. In this embodiment as well, the sections divided by theslits 6 can be bulged uniformly. -
FIG. 6 specifically shows an exemplary use of the expansion anchor shown inFIG. 3(A) . In this exemplary use, the expansion anchor is applied to a ceiling portion 1' of a tunnel, for example, and the fixingmale screw 16 provided at the base end of thehollow shaft 3 is exposed downward from the ceiling surface. Anupper piece 33a of a channel suspension fitting 33 is fixed to the ceiling surface using thenut 17, and asuspension bolt 34 is attached to thelower piece 33b of the suspension fitting 33. Thesuspension bolt 34 is used to suspend a ceiling panel or a ceiling frame. - A socket bolt in which a hexagonal hole is formed in its head is used as the
bolt 9 for expanding the radiallyexpansive portion 7, and the head is exposed downward from the ceiling surface (a bolt with a polygonal head can also be used) . It is possible to determine, by rotating thebolt 9 with atorque wrench 35, whether or not thehollow shaft 3 retains an appropriate withdrawal resistance. In this case, when thetorque wrench 35 indicates a predetermined value of measurement with thebolt 9 kept non-rotated, an appropriate withdrawal resistance is still retained, so that it is not necessary to take any specific countermeasure. - On the other hand, when the
bolt 9 rotates before the measurement of thetorque wrench 35 reaches the predetermined value, the biting force of the radiallyexpansive portion 7 against theinstallation region 1 may have decreased. Therefore, thebolt 9 is rotated until the measurement of the torque wrench increases to the predetermined value. In this way, the provision of the fixingmale screw 16 at the base end of thehollow shaft 3 enables the maintenance of the expansion anchor (adjustment of withdrawal resistance) without removing the suspension fitting 33. Therefore, the maintenance can be performed easily and efficiently. - It should be noted that, as a
bolt 9 for expanding the radiallyexpansive portion 7, use may be made of a hexagonal-socket bolt having no enlarged head or a bolt with a quadrangular head the circumcircle of which has a diameter equal to or smaller than the outer diameter of the screw thread. The use of such a bolt is advantageous in that it does not affect screwing of thenut 17. - The inventors of the present invention tested the performance of emodied products of the present invention.
FIG. 7 shows the test.FIGS. 7(A) and 7(B) show samples that were used in the test. The samples were similar to the first embodiment. The outer diameter was 10 mm, the entire length was 60 mm, the inner diameter of the hollow shaft was about 6 mm, and a 8-mm bolt was used as the bolt 9 (the inner diameter of the pre-formed hole of a 8-mm female screw corresponded to the inner diameter of the hollow shaft). - Regarding an A-type exemplary sample, the radially
expansive portion 7 had a length of about 25 mm, thehollow shaft 3 had a constant diameter over the entire length thereof, and the tip end was closed. Regarding a B-type exemplary sample, a portion of about 8 mm at the tip end was squeezed, and therefore, the radiallyexpansive portion 7 was shorter than that of the A type. In both samples, a plurality of diametrically different steel balls were used as the radially expanding action member. More specifically, one ball having an outer diameter of 6 mm, three balls having an outer diameter of 4.5 mm, three balls having an outer diameter of 5 mm, and one ball having an outer diameter of 6 mm were arranged in this order from thebolt 9 side. - A conventional product (commercially available product) C shown in
FIG. 7 (C) was used as a comparative example. Regarding this conventional product C, the entire length and outer diameter were the same as those of the two samples (60 mm, 10 mm), and four slits C2 were formed in the tip end side of a hollow shaft C1 to be open at the tip end face. Thus, a portion in which the slits were formed was an radially expansive portion C3 to be expanded into a flaring manner. A pin C4 was inserted into the hollow shaft C1 from the base end. The pin C4 had a tapering tip end. When the pin C4 was hit into the radially expansive portion C3, the radially expansive portion C3 was expanded. Therefore, the withdrawal resistance of this comparative example C became constant. - Two A-type samples and two B-type samples were manufactured, and the withdrawal resistance thereof was measured at varying screwing torques of the
bolt 9. The graph inFIG. 7(E) shows the results. Specifically, inFIG. 7(E) , the horizontal axis F indicates the screwing torque of thebolt 9, whereas the vertical axis S indicates the withdrawal resistance. A concrete block was used as a target product serving as the installation region. - A1 was an A type in which the outer circumference of the radially
expansive portion 7 was knurled, and A2 was an noraml A type in which the outer circumference of the radiallyexpansive portion 7 was smooth. B1 was a B type in which the outer circumference of the radiallyexpansive portion 7 was knurled, whereas B2 was a normal B type in which the outer circumference of the radiallyexpansive portion 7 was smooth. Knurling was performed in an inclined lattice pattern with a fine pitch. - The graph in
FIG. 7(E) clearly shows that the withdrawal resistance increases with an increase in the screwing torque of thebolt 9. It can be understood from these results that the withdrawal strength can be controlled to a desired level by controlling the torque of thebolt 9. It can also be understood that the withdrawal resistance increased due to knurling, and there was no significant difference between the A type and the B type. - The graph in
FIG. 7(D) shows relationship between the amount of shift of the expansion anchor and the withdrawal resistance when the expansion anchor was pulled using a drawing test machine. Specifically, in the graph inFIG. 7(D) , the horizontal axis indicates an axial shift, while the vertical axis indicates a withdrawal resistance. - The test used an
A1 type bolt 9 that was screwed at 20 KNm, anA1 type bolt 9 that was screwed at 8 KNm, and a comparative example C. In either of these samples, the withdrawal resistance of the anchor had a peak value, and the withdrawal resistance decreased with an increase of drawn amount after exceeding the peak value. Such a result was predictable. - On the other hand, in the graph in
FIG. 7(D) , it is noteworthy that, in the comparative example C, cone-type failure occurred in concrete due to a shift of more than 9 mm, so that no further drawing became impossible, whereas in both embodiments of the present invention did not suffer from cone-type failure. In particular, although the sample screwed at 20 KNm exhibited a withdrawal strength higher than the comparative example C, cone-type failure did not occur in the installation region. This fact shows that the embodied sample of the present invention is very useful in preventing cone-type failure. - The above-noted experiment, which was performed in a simple manner by the inventors of the present invention, is considered to clearly show the features of the present invention. It is believed that, in the future, better implementations may be provided by selecting the dimensions of various elements. An A type sample and a B type sample were prepared in which 6-mm balls were arranged one at each of the front end and the rear end and thirty 3-mm balls were arranged between both balls. Though the withdrawal resistance of these samples was not measured, the sections divided by the
slits 6 bulged substantially uniformly. - As a manner of arranging diametrically
different balls 10, a multiplicity of diametrically larger balls having substantially the same diameter as the inner diameter of the radiallyexpansive portion 7 are arranged, and a plurality of (e.g., four to six) diametrically smaller balls are arranged between adjacent ones of the diametrically larger balls generally at an axial center of the radiallyexpansive portion 7. In this example, it is expected that the sections divided by the slits bulge uniformly due to the plurality of diametrically smaller balls that are radially pushed by the two diametrically larger balls sandwiching them. - When the samples A and B shown in
FIG. 7 were examined, only a certain circumferential position of the radiallyexpansive portion 7 bulged largely. It is considered from this fact that, in order to increase the withdrawal resistance, the radiallyexpansive portion 7 need not bulge uniformly over the entire circumference, but rather deep biting engagement is important. - In this case, when bulging occurs at positions of the radially
expansive portion 7 that are displaced axially and circumferentially as shown inFIG. 8(A) , it is expected that a high withdrawal resistance can be obtained while suppressing an increase in compressive stress on the installation region 1 (thus preventing cone-type failure). It should be noted that, in the embodiment shown inFIG. 8(A) , themember 13 is fixed to theinstallation region 1 using thebolt 9 for bulging the radiallyexpansive portion 7. - When the radially
expansive portion 7 is divided by four slits, it is considered ideal that the four sections are bulged at alternately different positions which are displaced circumferentially and axially from each other as shown inFIG. 8(B) . When the radiallyexpansive portion 7 is divided by three slits, it is considered ideal that the three sections are bulged at alternately different positions which are displaced circumferentially and axially from each other as shown inFIG. 8(C) . Even when two bulges are located at the same axial position and at diametrically opposite positions with respect to the axis, it is considered possible to secure a high withdrawal resistance without causing cone-type failure. - When the balls (steel balls) 10 are used as the radially expanding action member, the
balls 10 come into contact with the radiallyexpansive portion 7 from the inside in an irregular manner. Therefore, it may be difficult to cause bulging of the radiallyexpansive portion 7 at positions that are axially displaced from each other. In one example of a countermeasure against this, as shown in an eighteenth embodiment shown inFIG. 8(D) ,auxiliary members 36 are inserted into the radiallyexpansive portion 7, so that the radiallyexpansive portion 7 is caused to bulge via theauxiliary members 36. - Specifically, the
auxiliary members 36 are arranged in corresponding relation to and without any circumferential shift from the sections of the radiallyexpansive portion 7 divided by the slits, andoutward protrusions 36a are provided at axially shifted positions on theauxiliary members 36 respectively. Theauxiliary members 36 have such a strength that they do not easily deform. When the group of theballs 10 are pushed by a bolt, theauxiliary members 36 are radially pushed, and the respective sections of the radiallyexpansive portion 7 are bulged due to theprotrusions 36a of theauxiliary members 36. - In a nineteenth embodiment shown in
FIG. 8(E) , at least the radiallyexpansive portion 7 is formed in an elliptic shape, and fourslits 6 are formed to circumferentially separate thin portions and thick portions. In this embodiment, the thin portions are concentratively deformed, so that the radiallyexpansive portion 7 can be easily bulged in a symmetrical manner. (The balls come into contact with the thin portions at axially separated positions. Therefore, even when the radiallyexpansive portion 7 is bulged in a symmetrical manner, the bulges are shifted in the axis direction.) - In a twentieth embodiment shown in
FIG. 8(F) , theslits 6 are formed at uneven intervals in the radiallyexpansive portion 7 which is perfectly circular, thereby providing easily deformable zones in the radiallyexpansive portion 7. In this case as well, so that the radiallyexpansive portion 7 can be easily bulged in a symmetrical manner. - In the case where a member is fixed using an anchor that is hit into a wall, for example, a downward load is applied to the member, so that a high withdrawal resistance can be obtained when the radially
expansive portion 7 bulges upward. In the embodiments shown inFIGS. 8(E) and 8(F) , the radiallyexpansive portion 7 bulges constantly in one direction. Therefore, when thehollow shaft 3 is set to assume a predetermined rotational orientation, the radiallyexpansive portion 7 can be made to bulge in a desired direction. This point is one of the advantages of the embodiments shown inFIGS. 8(E) and 8(F) . - In a twenty-first embodiment shown in FIG. 8(G), two
pins 37m 38 are inserted into thehollow shaft 3 at a forward position and a rearward position, respectively, and a plurality ofballs 10 are arranged between the two pins. Thepins rear side pin 38 is pushed using a bolt, theballs 10 are rearranged into a circumferential array due to the clamping action of thepins expansive portion 7 can be made to bulge accurately at a predetermined position. - The number of the
balls 10 may be set to be three to ten, for example. In this embodiment, when the twopins bolt 9 cannot be further screwed, consequently preventing the radiallyexpansive portion 7 from bulging excessively. In other words, in this embodiment, the maximum screwing torque of thebolt 9 can also be controlled. The tip ends of thepins - The features shown in FIG. 8(G) and the features shown in
FIG. 8(E) or 8(F) may be combined for causing the radiallyexpansive portion 7 to readily bulge at two opposite positions that are separated by 180 degrees. It is also possible to use three pins and arrangeballs 10 between the adjacent pins. In this case, two radiallyexpansive portions 7 are provided as axially separated from each other, so that the two radiallyexpansive portions 7 are separaly expansive using the balls. Therefore, the embodiment shown inFIG. 8(A) may be realized easily. Use may be made of four or more pins for bulging at three or more axially different portions. - In the twenty-first embodiment shown in FIG. 8(G), an
annular groove 39 is formed in the outer circumferential surface of thepin 38 at an rear end portion, and an O-ring (or a rubber ring) 40, which is an example of a removal restraining means, is fitted in theannular groove 39. The O-ring 40 is fitted into thehollow shaft 3 in an elastically deformed state, so that it does not remove easily. Therefore, theballs 10 are prevented from falling out due to careless handling during assembly. Even when thebolt 0 is removed after the installation, thepins balls 10 do not fall out. - The present invention may provide various other embodiments in addition to the above-described embodiments. For example, the radially expanding action member is not limited to those shown in the drawings, and any radially expanding action member may be used as long as it is capable of pressing against the radially expansive portion from the inside in response to a pushing action of the bolt. Therefore, a wire rod bent into a bow shape or a helically wound member such as a coil spring may also be used. When a helically wound member having a triangular or trapezoidal cross section is used, it is capable of providing a high radially expanding action.
- As a means for enhancing the ability of preventing the hollow shaft from withdrawal, the outer circumferential surface of the radially expansive portion may be provided with a multiplicity of projections. A member such as a suspension fitting may be welded in advance to the hollow shaft. Further, the hollow shaft, the radially expanding action member and the bolt may be made of a resin if there is no problem with respect to thermal resistance. The radially expansive portion may also be formed by replacing the slits with a multiplicity of holes or thin-walled sections.
- Regarding a means for preventing the radially expanding action member such as balls from falling out, a plug made of a soft material such as rubber, for example, may be inserted into the hollow shaft. The plug is crushed by the bolt, so that it does not pose any problem with respect to the function of pressing against the balls. When the bolt is removed, the plug is held inside the hollow shaft, so that the radially expanding action member such as balls can be prevented from falling out.
- As another removal preventing means, use may be made of a metal plug formed on its outer circumference with an annular groove for fitting an elastic ring such as an O-ring. In this case, the radially expanding action member such as balls is pressed by the bolt via the plug.
- The present invention can be practically embodied as an expansion anchor. Therefore, the present invention is industrially applicable.
-
- 1
- Installation region
- 2
- Pre-formed hole
- 3
- Hollow shaft
- 3a
- Tip end
- 3b
- Base end
- 4
- Flange
- 6
- Hole
- 7
- Radially expansive portion
- 8
- Female screw portion
- 9
- Bolt for expanding radially expansive portion
- 10
- Metal ball as an example of radially expanding action member
- 12
- Bolt for fastening a member
- 13
- Member attached using an expansion anchor
- 15
- Engaging male screw for engagement with a pre-formed hole
- 16
- Fixing male screw
- 17
- Nut
- 24
- Bowl-shaped element as an example of radially expanding action member
- 27
- Ring as an example of radially expanding action member
- 30
- Wavy element as an example of radially expanding action member
- 33
- Suspension fitting
- 34
- Suspension bolt
- 35
- Torque wrench
-
- 1. An expansion anchor comprising:
a hollow shaft to be inserted, from a tip end thereof, into a pre-formed hole formed in an installation region, and a bolt to be screwed into the hollow shaft from outside the installation region,
wherein the hollow shaft is formed with a radially expansive portion, that is weakened to be bulgeable, at a portion of the hollow shaft within the pre-formed hole and short of the tip end of the hollow shaft, and the hollow shaft is internally provided with a radially expanding action member that pushes the radially expansive portion radially outward in response to pushing action caused by screwing of the bolt into the hollow shaft. - 2. The expansion anchor according to
clause 1,
wherein the radially expansive portion of the hollow shaft is formed with a plurality of axially elongated slits that are circumferentially spaced from each other. - 3. The expansion anchor according to
clause
wherein the radially expanding action member includes a multiplicity of metal balls, and the radially expansive portion is allowed to bulgingly deform due to the balls moving radially outward in group in response to a push from the bolt. - 4. The expansion anchor according to
clause 3,
wherein the radially expansive portion has an axial length that is at least twice an outer diameter of the hollow shaft. - 5. The expansion anchor according to
clause 3,
wherein the hollow shaft is configured such that the other end is exposed outside the installation region, at least a portion of the hollow shaft that is exposed outside of the installation region is formed with fixing threads, and the fixing male screw is engageable with a nut for mounting another member.
Claims (3)
- An expansion anchor comprising:
a hollow shaft (3) to be inserted, from a tip end (3a) thereof, into a pre-formed hole (2) formed in an installation region (1), a bolt (9) to be screwed into the hollow shaft (3) from outside the installation region (1), and a multiplicity of metal balls (10) accommodated in an hole (5) of the hollow shaft (3) between the bolt (9) and the tip end (3a) of the hollow shaft (3);wherein the hollow shaft (3) is formed with a radially expansive portion (7) that is bulgingly deformed by the balls (10) moving radially outward in group in response to a push from the bolt (9) screwed into the hollow shaft (3);wherein the radially expansive portion (7) of the hollow shaft (3) is formed with a plurality of axially elongated slits (6) that are circumferentially spaced from each other; and characterized that the hollow shaft (3) is configured such that the other end is exposed outside the installation region (1), at least a portion of the hollow shaft (3) that is exposed outside of the installation region (1) is formed with fixing male threads (16), and the fixing male threads (16) are engageable with a nut (17) for mounting another member (13). - The expansion anchor according to claim 1,
wherein the radially expansive portion (7) has an axial length that is at least twice an outer diameter of the hollow shaft (3). - The expansion anchor according to claim 1 or 2,
wherein the balls (10) include diametrically different balls.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2015017018 | 2015-01-30 | ||
PCT/JP2016/052833 WO2016121993A1 (en) | 2015-01-30 | 2016-01-29 | Expansion anchor |
EP16743596.5A EP3252243B1 (en) | 2015-01-30 | 2016-01-29 | Expansion anchor |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP16743596.5A Division-Into EP3252243B1 (en) | 2015-01-30 | 2016-01-29 | Expansion anchor |
EP16743596.5A Division EP3252243B1 (en) | 2015-01-30 | 2016-01-29 | Expansion anchor |
Publications (2)
Publication Number | Publication Date |
---|---|
EP4137708A1 true EP4137708A1 (en) | 2023-02-22 |
EP4137708B1 EP4137708B1 (en) | 2023-11-22 |
Family
ID=56543595
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP16743596.5A Active EP3252243B1 (en) | 2015-01-30 | 2016-01-29 | Expansion anchor |
EP22200871.6A Active EP4137708B1 (en) | 2015-01-30 | 2016-01-29 | Expansion anchor |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP16743596.5A Active EP3252243B1 (en) | 2015-01-30 | 2016-01-29 | Expansion anchor |
Country Status (7)
Country | Link |
---|---|
US (1) | US10415620B2 (en) |
EP (2) | EP3252243B1 (en) |
JP (2) | JP6272513B2 (en) |
CN (1) | CN107429513B (en) |
AU (1) | AU2016212997B2 (en) |
SG (1) | SG11201706163YA (en) |
WO (1) | WO2016121993A1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6972104B2 (en) * | 2017-02-28 | 2021-11-24 | 土肥 雄治 | Expandable anchors and expansion devices used for them |
EP3845716A4 (en) | 2018-08-27 | 2022-09-14 | Yuji Dohi | Expansion-type anchor, sleeve used in same, and construction method |
JP2020084476A (en) * | 2018-11-20 | 2020-06-04 | 敏次 浜田 | Self-perforating expansion type anchor and driver bit used therefor |
JP7304613B2 (en) * | 2019-03-07 | 2023-07-07 | 日本パワーファスニング株式会社 | Extraction device for expandable anchors |
US11274695B2 (en) * | 2020-01-14 | 2022-03-15 | Eve Ventures Llc | Expanding, anchoring screw |
JP6967307B1 (en) * | 2020-09-02 | 2021-11-17 | 日本パワーファスニング株式会社 | Expandable anchor removal device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5124450A (en) * | 1974-05-02 | 1976-02-27 | Hilti Ag | |
US3945294A (en) * | 1974-05-28 | 1976-03-23 | Virgil Hinson | Expandable anchor bolt |
JPS526970U (en) | 1975-07-03 | 1977-01-18 | ||
JP3007126U (en) | 1994-07-22 | 1995-02-07 | 日本ドライブイット株式会社 | Expanded anchor for concrete |
JP2004218421A (en) | 2003-01-09 | 2004-08-05 | Kyoa Kikai Kofun Yugenkoshi | Ball pressure type extension anchor |
Family Cites Families (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US734326A (en) * | 1902-10-20 | 1903-07-21 | Thomas P Hicks | Device for fastening metal, &c., to stone. |
US754764A (en) * | 1903-04-22 | 1904-03-15 | John Orr | Expansion-bolt. |
US1630499A (en) * | 1921-06-09 | 1927-05-31 | Stewart Warner Speedometer | Expansible shackle bolt and the like |
USRE16062E (en) * | 1921-08-11 | 1925-05-05 | Bolt anchor | |
US2535079A (en) * | 1944-05-02 | 1950-12-26 | United Air Lines Inc | Method of upsetting a hollow rivet |
US2872838A (en) * | 1954-05-24 | 1959-02-10 | Alvin R Vogel | Controllably expandable and removable fastener |
US2950602A (en) * | 1956-11-20 | 1960-08-30 | Joseph C Lang | Expansion device |
DK125488B (en) * | 1969-05-30 | 1973-02-26 | L Mortensen | Tubular expansion dowel body or similar fastener and method of making the same. |
IL40658A (en) * | 1972-10-25 | 1974-11-29 | Doriel J | Modular building method and building elements |
JPS526970A (en) | 1975-07-07 | 1977-01-19 | Fujitsu Ltd | Surface coating of high density terminal plate |
US4954017A (en) * | 1980-11-10 | 1990-09-04 | The Curators Of The University Of Missouri | Expansion bolt and mine roof reinforcement |
US5271700A (en) * | 1989-05-16 | 1993-12-21 | Acb | Fixing member |
JPH0427209U (en) | 1990-06-29 | 1992-03-04 | ||
US5975788A (en) * | 1998-07-20 | 1999-11-02 | Cousins; Joseph Russell | Locating apparatus |
TW577493U (en) | 2003-01-09 | 2004-02-21 | Great Asia Machinery Co Ltd | Internal driving type expansion bolt |
CN2898168Y (en) * | 2006-04-16 | 2007-05-09 | 泓泰复合材料(江阴)有限公司 | Side hidden anchor fastener of composite thermal-insulation board |
CN201043342Y (en) * | 2007-02-15 | 2008-04-02 | 慧鱼(太仓)建筑锚栓有限公司 | Expansible and knotted anchor bolt of heat-preserving system |
CN201172939Y (en) * | 2008-04-08 | 2008-12-31 | 刘建康 | Fastener for hollow building block |
US20100096792A1 (en) * | 2008-10-20 | 2010-04-22 | Ludwig Demmeler | Clamping Device |
JP2013108544A (en) * | 2011-11-18 | 2013-06-06 | Marutaka Kogyo:Kk | Bolt |
DE202013010334U1 (en) | 2013-11-15 | 2014-03-06 | Joachim Müller | Clamping bolt with balls and spring clamping straps |
-
2016
- 2016-01-29 AU AU2016212997A patent/AU2016212997B2/en active Active
- 2016-01-29 WO PCT/JP2016/052833 patent/WO2016121993A1/en active Application Filing
- 2016-01-29 EP EP16743596.5A patent/EP3252243B1/en active Active
- 2016-01-29 CN CN201680007924.1A patent/CN107429513B/en active Active
- 2016-01-29 US US15/547,349 patent/US10415620B2/en active Active
- 2016-01-29 JP JP2016572212A patent/JP6272513B2/en active Active
- 2016-01-29 SG SG11201706163YA patent/SG11201706163YA/en unknown
- 2016-01-29 EP EP22200871.6A patent/EP4137708B1/en active Active
-
2017
- 2017-12-28 JP JP2017253002A patent/JP2018080839A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5124450A (en) * | 1974-05-02 | 1976-02-27 | Hilti Ag | |
US3945294A (en) * | 1974-05-28 | 1976-03-23 | Virgil Hinson | Expandable anchor bolt |
JPS526970U (en) | 1975-07-03 | 1977-01-18 | ||
JP3007126U (en) | 1994-07-22 | 1995-02-07 | 日本ドライブイット株式会社 | Expanded anchor for concrete |
JP2004218421A (en) | 2003-01-09 | 2004-08-05 | Kyoa Kikai Kofun Yugenkoshi | Ball pressure type extension anchor |
Also Published As
Publication number | Publication date |
---|---|
US20180023606A1 (en) | 2018-01-25 |
SG11201706163YA (en) | 2017-09-28 |
CN107429513B (en) | 2021-02-12 |
WO2016121993A1 (en) | 2016-08-04 |
JP2018080839A (en) | 2018-05-24 |
EP3252243B1 (en) | 2022-11-30 |
AU2016212997A1 (en) | 2017-08-17 |
EP4137708B1 (en) | 2023-11-22 |
AU2016212997B2 (en) | 2020-11-12 |
EP3252243A4 (en) | 2018-11-07 |
CN107429513A (en) | 2017-12-01 |
US10415620B2 (en) | 2019-09-17 |
EP3252243A1 (en) | 2017-12-06 |
JP6272513B2 (en) | 2018-01-31 |
JPWO2016121993A1 (en) | 2017-12-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP3252243B1 (en) | Expansion anchor | |
US8974163B2 (en) | Wedge-type drop-in anchor assembly | |
AU695102B1 (en) | Expansion anchor and method therefor | |
EP2623797B1 (en) | Anchor and method of installing anchor | |
US8621742B1 (en) | Ferrule lock nuts method | |
CN108138827B (en) | Thread forming screw with independent thread spirals and different thread flank angles | |
EP2065601B1 (en) | Expansion anchor | |
KR102023209B1 (en) | Splined fastener | |
KR20130084223A (en) | Expanding anchor | |
JP4133826B2 (en) | Fastening method | |
EP1357302B1 (en) | Removable deep set drop-in anchor | |
EP2522862A1 (en) | Fastening assembly | |
US6835036B2 (en) | Concrete anchor | |
US6447227B1 (en) | Threaded fastener | |
AU2018226614B2 (en) | Anchor bolt | |
US10344790B2 (en) | Masonry anchor of the expansion type | |
US20020100346A1 (en) | Self-locking fastener system and process | |
WO2018159697A1 (en) | Expanding-type anchor and expanding member used therein | |
GB2153475A (en) | Anchoring of rock bolts |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN PUBLISHED |
|
AC | Divisional application: reference to earlier application |
Ref document number: 3252243 Country of ref document: EP Kind code of ref document: P |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
|
17P | Request for examination filed |
Effective date: 20230330 |
|
RBV | Designated contracting states (corrected) |
Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: GRANT OF PATENT IS INTENDED |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: F16B 37/12 20060101ALN20230703BHEP Ipc: F16B 35/00 20060101ALN20230703BHEP Ipc: F16B 13/12 20060101ALI20230703BHEP Ipc: F16B 13/08 20060101AFI20230703BHEP |
|
INTG | Intention to grant announced |
Effective date: 20230718 |
|
P01 | Opt-out of the competence of the unified patent court (upc) registered |
Effective date: 20230829 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE PATENT HAS BEEN GRANTED |
|
AC | Divisional application: reference to earlier application |
Ref document number: 3252243 Country of ref document: EP Kind code of ref document: P |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP Ref country code: DE Ref legal event code: R096 Ref document number: 602016084356 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: LT Ref legal event code: MG9D |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: MP Effective date: 20231122 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240223 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240322 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: MK05 Ref document number: 1634094 Country of ref document: AT Kind code of ref document: T Effective date: 20231122 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: ES Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: LT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240322 Ref country code: GR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240223 Ref country code: ES Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: BG Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240222 Ref country code: AT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: PT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240322 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20240111 Year of fee payment: 9 Ref country code: GB Payment date: 20240216 Year of fee payment: 9 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: RS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: PL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: NO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240222 Ref country code: LV Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 Ref country code: HR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20231122 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20240118 Year of fee payment: 9 |